General Electric AC4400
The GE AC4400CW is a 4,400 horsepower (3,300 kW) diesel-electric locomotive that was built by GE Transportation Systems between 1993 and 2004. It is similar to the Dash 9-44CW, but features AC traction motors instead of DC, with a separate inverter per motor. 2,598 examples of this locomotive were produced for North American railroads. These locomotives are similar in appearance to GE's more powerful locomotive the AC6000CW. As a result of more stringent emissions requirements that came into effect in the United States on January 1, 2005, the AC4400CW has been replaced by the GE ES44AC.
As of 2005, every Class I railroad with the exceptions of Norfolk Southern, Canadian National, and Amtrak owns at least one AC4400CW. These units quickly gained a reputation as powerful freight haulers, especially in heavy-haul applications.
The AC4400CW was the first GE locomotive to offer an optional self-steering truck design, intended to increase adhesion and reduce wear on the railhead. This option was specified by Canadian Pacific, Cartier Railway, CSX, Ferromex, Ferrosur, and KCS.
Digitrax General Electric AC4400 Sound scheme. Copyright (c) Digitrax Inc.
Digitrax General Electric AC4400 Sound scheme. Copright (c) Digitrax Inc.
Digitrax Kato AC4400 / SDH104k1A - SOUND Decoder "VERSION 4" Oct 9th 2007
This is a modified NOTCH scheme and includes a "short horn blow" capability using CV156 - Moved F10 sequence to same priority as F7, AVOIDS scattered air events (F4 off) causing delays
EVO SDF: Ac4400 Diesel Scheme
Author AJ Ireland
(A) Function Key Usage:
F2- Horn, [CV150 selects Horn type]
F3- Coupler crash [Autocoupler/brake set by CV151 max spd]
F4- Air feature disable- F4 to OFF enables pop-off,drier and starts compressor
F5- Dynamic brake Fans
F6- Manual Notch UP, if CV155 is not 00
F7- Crossing Gate Airhorn - or Manual Notch DOWN, if CV155 is not 00
F8- Mute control, [F8 ON is muted.]
F9- Brake squeal
F10- Crossing gate Airhorn sequence
(B) AC4400 Sound FX defined CV's: [decoder CV8=8 Factory reset value in sq. brackets]
CV58 Master Volume, 0-15, 0= max, (F8 used for Mute) 
CV121 Software Version, MUST be 2 or higher  (Read Only Value)
CV122 Product TYpe, 12 = Digitrax SFX sound decoder  (Read Only Value)
CV123 Hardware Version, 17= SDH104K1 decoder  (Read Only Value)
CV124 Flash Signature  (Read Only Value)
CV125 16KB free blocks  (Read Only Value)
CV126 FAT flags  (Read Only Value)
CV127 Internal Flags  (Read Only Value)
CV128 IPL counter  (Read Only Value)
CV132 Notch rate 
CV135 Volume when Muted 
User configurable SoundCV's:
CV140 PRIME mover vol 0-64 
CV141 BELL vol 0-64 
CV142 WHISTLE volume 0-64 
CV143 Air features volume (popoff, drier,comp) 0-64 
CV145 Misc vols 0-64 
CV146 BELL delay (24mS counts) 1-100 
CV147 Drier rate, 1= about 2secs 1-64 
CV148 Compressor Start rate 
CV149 COMPRESSOR ON time 
CV150 Horn Selector 0=std Horn , 1=Playable volume Horn 2=Alternate Horn 
CV151 PEAK speed to allow AUTO coupler/brake on DIR change and F3 on. 0-60 
CV152 Author ID Digitrax=0xdd 
CV153 Project ID AC4400 
CV155 Notching Mode,0=AUTO, 1=SEMIAUTO,2=MANUAL NOTCHES 
CV156 Horn DELAY Thresold 
CV160 Variant ID 
(C) General Notes
Sound recordings courtesy of Paul Knowles, AJ Ireland and Charlie Brown.
The SDH104K1 decoder is used in conjunction with FN04 4 line FX3-type function decoder. SDH104K1 responds as per standard FX3 decoder (e.g. DH163D)for CV1-120. FN04 does not respond to/execute any CV programming in SoundCV (SCV) range CV121-255.
Both decoders have CV15/16 lock capability for advanced users.
For CV155=01 ["Semi_automatic Notching"], the Prime mover lowest Notch setting is set by the throttle speed setting. F6 (ON) can increase the Notch and F7 (ON) will decrease the Prime mover to the minimum notch set by current throttle setting.
Digitrax Kato AC4400 / SDH104k1A - SOUND Decoder "VERSION 4" Oct 9th 2007 This is a modified NOTCH scheme and includes a "short horn blow" capability using CV156 - Moved F10 sequence to same priority as F7, AVOIDS scattered air events (F4 off) causing delays project: ac4400_4.spj EVO SDF: Ac4400 Diesel Scheme Author AJ Ireland Digitrax Inc.
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